Tap changer



L.'H. HILL TAP CHANGER Aug. 20, 1929.

` 2 sheets-sheet Filed March 3l, 1926 WITNEssEs:

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ATTORNEY Aug.2o,1929. L.H.H|LL y 1,725,078

' vTAP CHANGER Filed March 31, 1926 2 Sheets-Sheet 2 l nl@ WITNESSES: INVENTOR amlm e/md//f/V/ Patented V20,

j "UNIT-ED .STATES PATENT OFFICE. I

H. m, F SWILSSVALE, FENNSYLVANIA, ASSIGNOB TO -'WESTING'HOUSE ELECTRIC- MANUFACTURING COMPANY, A CORPORATION 0F PENNSYLVANIA.

mi CHANGER..

- appuoacionrmea man a1, 192e.- semi iro. 9am.

My invention relates to electrical switching 4vmechanisms and particularly to tap changers forA transformers or other appa. ratus. Y -v- 6 On'e object of my invention is to provide a tap-changing device that 'shall be in unstable equilibrium duriiig the operation of tap changing. l

A further object of my inventin is to .'10 provide a tap changer in which the bridging K mlember has a partial-'turning'- movement aboutv the stationary contact member that y it is facing.

V y In changing the vtap connection of `the electrical transformers, it is yery im ortant that the service be uninterrupted or the least possible time. 'It is desirable that a tap' changer shall not remain in a position in which the transformer circuit is incomi plete.

In the accompanying drawings, Figure 1 is a flan view, partially in section, of a tap-changing device embodying my invention.

Fig. 2 is a sectional view taken along the sectionl line II -II of Fig. 1. 'n

Fig. 3 is4 a plan view of m improved tapA changer immediately prece ing its transition from one tap connection to another'. l

Fig.` 4 is asimilar view of the tap changer `slowing' inffull lines the position assumed during the first movements of separation of the'tap changer, and, in dotted lines, the position assumed at the end of the,tap

- 35 changing operation.

My vention comprises, iii general, a pair of base plates 1 of suitable insulating material' between which are mounted a plurality of stationary contact members 2, connected 1,40 to transformer windings (not shown), and

arranged in the circumference of a circle. A movable bridging member 3 of arcuate contourispivotally mounted on'. support 4,l that is, in turn, mounted on a shaft 5 cenitrally disposed relative t the stationary Contact members 2. The bridging'member 3 is adapted to engage two adjacent stationary contact members 2 simultaneously.

Referring particularly .to Figs.- 1 and 2,

the support 4 comprises a clamp -6 that is mounted about the shaft 5 and which suports a pair of outwardly extending rods 7 f between which a coil ring 8 is `mounted.

A lu 9cextends outwar ly from the clamp 6 66 -withmthe convolutions of the aging 8 and .Y suitable mechanism not s engages a cylindrical member 11, thereby constituting a telescopic connection. The spring 8 presses v.againstla yoke 'or header member 12 that is slidably mounted on the rods 7.- The yoke 12 supports a shaft 13 that, in turn, supports a pair of arcuate members 14 ofvconducting material that tother constitute the bridgingV member 3. ccordingly,-the bridging member 3 is capable of turning relative to the yoke'12, and at the same time the bridgin member 3 and the support 4 may be rotate by moving the shaft 5 by a hand wheel, crank, or any othery wn In the operatio'n o a tap chaiiger embodying my invention, the shaft 5 is turned carrying with lit the rods 7 and the brid 'ng member 3, and the surfaces of the mem ers 14 slide'along the surfaces of the stationary contact members-2, with which they are engaged. This motion is not a tru'e movement oftranslation but partakes of a turning movement around a stationary contact memthe position shown in Fig. 1, to the position shown in Fi I3. Durin this movement, the spring 8 is compresse and the oke 12 moves inwardly along the rods 7. go long as the spring 8 is underyempression; the tap chan er is in a state of unstable equilibrium an tends to return to the position shown in Fig. 1.

During the foregoing movement, contact is not broken, between the adjacent stationary contact members 2, although it isto be noted that the motion of the bridging mem- 'ber 3 -isrelatively slow compared with thatv of support 4f.V However, as soon as the shaft 13 crosses the center line of the shaft 5 and one of. the stationary contact members 2,

the spring 8 expandsf thereby causing the 100 bridgin member 3 tomove rapidly across the sur ace. of the stationary contact member 2 againstlwhich it is bearing, and into engagement .with the next stationary cony tact member 2, thereby completing a new circuit.

It will be thus observed that I have provided a tap-changingswitch that is in aposition of unstable equilibrium when itis not completing. the connection between adjacent lio stationary contact members. The operation of circuit interruption is relatively slow as compared to the operation of circuit engagement, since compressive during the former operation that are 'liberated to accelerate the latter operation.

supporting structure mounted centrally o f and Wholly within the stationary fcontact members, and a bridgingmember for'simultaneously coacting with a (plurality of said members pivotally 'mounte ing structure whereby the bridging member has a turning movement about the station,-

- ary contact members during its engagement prising a shaft, guide rods mounted thereon,

therewith.

2. The combination with a plurality of circumferentially disposed stationary contact members, of an arcuate sha d bridging member and a pivoted support t erefor coma coil spring mounted between the guide rods, an

mounted on the rods and biased in an outward position by thesprin 3. The combination wit a plurality of stationary vcontact members, of a rotatable member, a second rotatable member carried thereby, and a contact-making member carried by said second named rotatable member for simultaneously coacting with a plurality 4of said contact members and means for biasing saidr `contact-making member from said first-named rotatable member.

1. The combination with a plurality of forces are stored v on the support-:

a yoke member forpivotall sup-A ,porting the bridging member and t'at is stationary contact members, of' a'rotatable member, `a second rotatable member carried by said {irst named rotatable member and movable toward land from the same, and a by said first namedY rotatable member and movable toward and from thesame, a contact-making member carried by said second named rotatable member for simultaneously coacting with a plurality of said contact members, and means for biasing said contact-making member y toward said contact members. y

6. The combination with a plurality of stationary contact members, of a rotatable member, a guide rod carriedby said rotatable member, a second rotatable member slidable along said guide rod, a helical spring interposed between said rotatable members, and a contact-making member car ried by said second named rotatable member for simultaneously coactin'g with a plurality of said contact members. Y

7. The combination with a plurality of stationary contact members of a rotatable member, a guide rod carried by said rotatable member, a yoke slidable on said guide rod, a second rotatable member carried by said yoke, means for biasing said yoke from said first named rotatable member, and a contact-making member carried by said second named rotatable member for simultaneously coacting with a pluralidty of said .LELAND H. HILL,y 

